Pressurized Hole Packing Screen Pipe for Soft Coal Seam Borehole Stability
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Solution Overview
Problem
In coal mining, soft coal seams with high stress and large mining depths lead to frequent coal disasters due to gas outbursts, as boreholes are prone to collapse and inefficient gas drainage, resulting in reduced effective drainage time and efficiency.
Innovation Solution
A full-length screen pipe hole protection device with pressurized hole packing, comprising a drainage pipe, sealing plugs, grouting pressure pump, and metal baffle plates, filled with a pressurized sealing material, is used to stabilize boreholes and enhance gas drainage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional borehole drainage is used in soft coal seams with high stress, then gas drainage can be performed, but the borehole structure becomes unstable and prone to collapse
Solution Approach 1:
The patent applies preliminary action by installing the screen pipe structure and sealing plugs into the borehole before conducting gas drainage operations. The screen pipe is预先 fixed with metal baffle plates and sealing plugs are positioned at the hole mouth segment, creating a protective framework in advance that prevents coal mass deformation and borehole collapse during the drainage process.
Solution Approach 2:
The patent employs composite materials by combining the screen pipe structure with metal baffle plates and sealing plugs to create a composite support system. This composite structure integrates multiple functional components (screen pipe for filtration, metal baffle plates for structural support, sealing plugs for isolation) that work together to enhance borehole stability and resist coal mass deformation under high stress conditions.
2Productivity
If boreholes are drilled in soft coal seams with large mining depth, then gas drainage is achieved, but the effective drainage time is reduced due to borehole collapse
Solution Approach 1:
The patent applies preliminary action by pre-installing the screen pipe structure with metal baffle plates and sealing plugs before gas drainage operations begin. This preliminary structural preparation prevents borehole collapse during the drainage process, ensuring that the borehole remains open and functional for the intended duration, thereby maintaining effective drainage time despite large mining depths and high stress conditions.
3Quantity of substance
If high stress and large mining depth are present, then coal gas can be extracted, but the borehole structure becomes unstable
Solution Approach 1:
The patent employs composite materials by creating a composite support structure consisting of the screen pipe, metal baffle plates, and sealing plugs. This composite system distributes and resists the high stress forces acting on the borehole, maintaining structural stability while enabling gas extraction from deep coal seams. The combined structure provides both mechanical support and functional capabilities for gas drainage.
Solution Approach 2:
The patent applies segmentation by dividing the borehole structure into multiple functional segments: the screen pipe segment for gas filtration and drainage, the metal baffle plate segments for structural reinforcement at intervals, and the sealing plug segments for isolating different zones. This segmented approach allows each component to independently address specific structural challenges posed by high stress and deep mining conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents borehole collapse, increases gas drainage efficiency, and reduces the likelihood of gas accidents by stabilizing the borehole structure and ensuring reliable gas extraction.
Implementation Method 1
a grouting pressure pump is connected to the grouting pipe protruded into the sealed space
Implementation Method 2
the grout discharge pipe is in communication with the sealed space
Data Source
AI summary
A full-length screen pipe hole protection device and method with pressurized hole packing in a soft coal seam relates to the field of gas drainage technologies. The device includes a grouting system, a drainage system and a hole fixing system. The grouting system injects a pressurized sealing material into a borehole through a pressure pump to increase a sealing effect of the borehole. The drainage system drains gas in the middle of air holes on metal baffle plates and hole fixing screen pipes through a drainage pipe to increase flowability of gas. The hole fixing system is inside the borehole and fixed with the metal baffle plates, and the hole fixing screen pipes are fixedly connected with each other through fitting mouths and fitting buckles. The device is fixedly mounted in the gas drainage borehole. After hole packing, the drainage pipe is connected with a drainage pump to drain gas.